Note: Descriptions are shown in the official language in which they were submitted.
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BAYER AKTIENGESELLSC~IAFT 51368 Leverkusen
Konzernzentrale RP
Patente Konzern GM/m-SP
5 A METHOD OF MANUFACTURING FOAM MATERIALS CONTAINING
RIGID URET~ANE AND OPTIONAL ISOCYANURATE GROUPS
BACKGROUND OF THE INVENTION
The invention relates to use of pulverulent polyurethane (PUR) rigid foam waste
occurring in the manufacture of PUR rigid foam materials in a proportion of 3 to10 25 wt.% depending on the application. There is a general problem of usefully
disposing of this waste.
Re-use of ground PUR rigid foam production waste in PUR rigid foam materials
is the nearest approach to recycling, along with the possibilities of combustion,
compression of gr~n~ tes or solvolysis.
1 5 It is known to improve individual properties (e.g. hardness) of rigid foam by using
finely-divided, insoluble, non-reactive fillers less than 0.25 mm in diameter and in
proportions up to 40 wt.% as described in, for example, German Offenlegungs-
schrift 2,024,810, or quartz sand of undefined particle size in about 30 to 80 wt.%
as described in, for example, German Offenlegungschrift 2,617,358. It is also
20 known to manufacture soft foam by using very fine-grain soft PUR foam meal
which occurs as waste during the manufacturing process.
Finely-divided fillers of this kind, made from soft foam m~t~ri~, are, of course,
of a suitable nature for being incorporated into the PUR matrix. The level of
mechanical properties can be maint~ined simply by ch~n~in~ the formulation.
25 Other finely-divided solids (such as melamine or ammonium polyphosphate) havenot hitherto been used in practice in rigid PUR foam m~t~ri~ . Aside from bubbleformation, open cells and inferior mechanical properties, the main problem, is that
the foam material is brittle (compare Table 1, Examples 1 and 2 in relation to
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Table 2, Examples 3 to 11). Consequently, these filled PUR rigid foam m~teri~l~
have not been used in practice.
It has now unexpectedly been found that operating with a device such as that
described in, for example, German Auslegeschrift 3,841,671 (believed to
correspond to U.S. Patent 5,152,943) and/or European Patent Application 431,388,the disclosures of which are herein incorporated by reference, rigid PUR foam
powder in surprisingly coarse grains can be used in a proportion up to 10 wt.% in
the production of low-density rigid PUR foam m~t~ri~l~, without the afore-
mentioned adverse effects such as brittleness.
Other solid fillers (Table 1) increase the gross density and brittleness of the foam
material but have no advantageous influence on the mechanical properties such as,
for example, bending strength when heated. By comparison, in the method
according to the invention, polyol and isocyanate are replaced weight for weightby solid polyurethane powder, with the resulting properties at comparable gross
density being the same as for non-filled foam material (Table 2). There is no
increase in brittleness.
SIJMMARY OF THE INVENTION
The invention relates to a process for the production of foam materials cont~ining
rigid urethane and/or optionally isocyanurate groups. This process comprises thesteps of reacting
a) one or more polyisocyanates,
with
b) one or more compounds c-)nt~ining at least two hydrogen atoms capable of
reacting with isocyanate groups and having a molecular weight of 400 to
10,000,
in the presence of
c) one or more organic fillers
and
d) water and/or one or more foaming agents wherein said foaming agents
comprise light volatile organic substances,
wherein the organic filler c) consists essentially of a polyurethane rigid foam
powder.
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The reaction of polyisocyanates and compounds cont~inin~ at least two hydrogen
atoms capable of reacting with isocyanates and having a molecular weigh~ of 400
to 10,000 may additionally occur in the presence of
e) compounds cont~inin~ at least two hydrogen atoms capable of reacting
with isocyanates and having a molecular weight of 32 to 399
and/or
f~ known auxiliary substances and additives.
According to the invention, the particle size of the polyurethane rigid foam
powder is advantageously in the range from 0.3 to 2.0 mm, and preferably 0.5 to
1.0 mm. Therefore, preference is given to filled, rigid PUR foam materials that
contain rigid PUR foam powder having a particle size of between 0.5 and 1.0 mm
in diameter.
According to the invention, it is also possible to use polyurethane rigid foam
powders which contain impurities, such as, for example, paper or fibers. The
presence of these impurities is due to the manuf~ctllring process of the poly-
urethane rigid foam from which the powders are produced.
The foam materials cont~ining rigid urethane groups and/or, optionally, iso-
cyanurate groups are produced from suitable materials such as those described
hereinbelow.
Suitable isocyanates for the process of the present invention include, for example,
aliphatic, cycloaliphatic, araliphatic, aromatic or heterocyclic polyisocyanates,
described e.g. by W. Siefken in Justus Liebigs Annalen der Chemie, 562, pages 75to 136, e.g. substances having the formula:
Q(NCO)n
in which
n equals 2-4, preferably 2-3, and
Q denotes an aliphatic hydrocarbon radical having 2 to 18, preferably 6 to 10
carbon atoms; a cycloaliphatic hydrocarbon radical having 4 to 15,
preferably 5 to 10 carbon atoms; an aromatic hydrocarbon radical having 6
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to 15, preferably 6 to 13 carbon atoms; or an araliphatic hydrocarbon
radical having 8 to 15, preferably 8 to 13 carbon atoms.
Some examples of such polyisocyanates include those described in, for example,
German Offenlegungschrift 2,832,253, pages 10-11, the disclosure of which is
herein incorporated by reference. As a rule, particular preference is given to
polyisocyanates which are easily and readily available in industry such as, for
example, 2,4 and 2,6-toluylene diisocyanate, or any mixtures of these isomers
("TDI"); polyphenyl polymethylene polyisocyanates produced by conri~n~tion of
aniline and formaldehyde and subsequent phosgenation ("crude MDI") and
polyisocyanates ("modified polyisocyanates") cont~inin~ carbodiimide groups,
urethane groups, allophanate groups, isocyanurate groups, urea groups or biuret
groups, particularly modified polyisocyanates derived from 2,4- and/or 2,6-
toluylene diisocyanate or from 4,4'- and/or 2,4'-diphenyl methane diisocyanate.
The process of the invention also requires, as starting cbmponents, compounds
cont~inin~ at least two hydrogen atoms capable of reacting with isocyanates and
having a molecular weight of from about 400 to 10,000. These compounds include
compounds cont~ining amino groups, thio groups, carboxyl groups, or, preferably,hydroxyl groups, and particularly compounds cont~ining from 2 to 8 hydroxyl
groups, especially those compounds having a molecular weight of 1,000 to 6,000,
and preferably of 2,000 to 6,000. Suitable examples include polyethers or
polyesters containing at least two, preferably 2 to 8, and most preferably. 2 to 6
hydroxyl groups, or polycarbonates and polyester amides such as those known per
se in the manufacture of homogeneous and cellular polyurethanes and are
described in, for example, German Offenlegung-schrift 2,832,253, pages 11-18, the
disclosure of which is herein incorporated by reference.
The organic fillers suitable for the present invention include, for example, those
polyurethane hard foam powders previously described above.
Suitable compounds to be used as foaming agents include, for example, water
and/or the light volatile organic substances known per se. In particular, the light
volatile organic substances are preferably selected from the group consisting ofpentane, isopentane, cyclopentane, hexafluorobutane, pentafluoropropane, and
mixtures thereof.
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In addition, the starting components may also be compounds having at least two
hydrogen atoms capable of reacting with isocyanate groups and having a
molecular weight of 32 to 399. These low molecular weight active hydrogen
cont~ining components may contain active hydrogen atoms in the form of, for
5 example, hydroxyl groups, amino groups, thiol groups, carboxyl groups, or
mixtures thereof. It is preferred that these compounds contain hydroxyl groups
and/or amino groups, and function as chain-lengthening agents or cross-linking
agents. These compounds usually have 2 to 8, preferably 2 to 4 active hydrogen
atoms which are capable of reacting with isocyanate groups. Suitable examples of1 0 such compounds are described in, for example, German Offenlegung-schrift
2,832,253, pages 19 - 20, the disclosure of which is herein incorporated by
reference.
It is also within the scope of the present invention that the starting components
may optionally include auxiliary substances and additives such as, for example,
1 5 catalysts of known kind in quantities of up to 10% by weight, based on the weight
of component b); surface-active additives such as, for- example, emulsifiers andfoam stabilizers; and retarders such as, for example, acid-reacting substances such
as hydrochloric acid or organic acid halides, or cell regulators of known kind such
as paraffins or fatty alcohols or dimethyl polysiloxanes or pigments or dyestuffs
20 and flame retardants of known kind, e.g. tricresyl phosphate, or stabilizers against
ageing and weather, plasticizers or fungistatic and bacteriostatic substances orother fillers such as barium sulphate, kieselguhr, carbon black or whiting.
These optional auxiliary substances and additives include materials such as those
described in, for example, German Offenlegung-schrift 2,732,292, pages 21 - 24,
25 the disclosure of which is herein incorporated by reference.
Suitable examples of other optional additives which may be used according to theinvention include, for example, surface-active additives and foam stabilizers and
cell regulators, retarders, stabilizers, flame-retarding substances, plasticizers,
dyestuffs and other fillers and fungistatic and bacteriostatic substances. Specific
30 details about the use and operation of these additives, are described in Kunststoff-
Handbuch, Volume VII, published by Vieweg and Hochtlen, Carl-Hanser-Verlag,
Munich 1966, e.g. on pages 103 - 113.
- 5 -
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A suitable method of producing rigid polyurethane foam materials is presented
below.
The components may be reacted in the known single-stage process, the prepolymer
process or the semi-prepolymer process, often using machinery such as that
described in, for example, U.S. Patent 2,764,565, the disclosure of which is herein
incorporated by reference. Details of processing equipment which can also be used
according to the invention are described in Kunststoff-Handbuch, Volume VII,
published by Vieweg and Hochtlen, Carl-Hanser-Verlag, Munich 1966, e.g. on
pages 121 to 205.
1 0 The foam materials can be made by, for example, slab production or by the known
double conveyor-belt method.
The products obtainable according to the invention are suitable for use as, for
example, insulating slabs for roofs.
The invention is further illustrated but is not intended to be limited by the
1 5 following examples in which all parts and percentages are by weight unless otherwise specified.
EXAl\IPLES
The polyurethane foam materials were produced by using polyol formulations A
and B described hereinbelow.
Formulation A
A polyol mixture having an OH number of 553 was prepared by mixing the
following components:
1. 26.9 parts of a polyether polyol having an OH number of 380, and was
prepared by the propoxylation of a mixture of saccharose, propylene glycol
and water;
2. 22.0 parts of a polyether polyol having an OH number of 620, and was
prepared by the propoxylation of ethylene diamine;
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3. 16.0 parts of a polyether polyol having an OH number of 445, and was
prepared by the propoxylation of a saccharose and ethylene glycol rnixture;
4. 13.0 parts of a polyether polyol having an OH number of 460, and was
prepared by the propoxylation and ethoxylation of ortho toluylene diamine;
5. 10.0 parts of glycerol as a cross-linking agent;
6. 1.6 parts of water as a co-foaming agent;
7. 9.0 parts of tris (~3-chloroisopropyl)phosphate (flame retardant); and
8 1.5 parts of a polyether polyol-modified polysiloxane foam stabilizer.
Formulation B
10 A polyol mixture having an OH number of 404 was prepared by mixing the
following components
1. 34.0 parts of a polyether polyol having an OH number of 380, and was
prepared by the propoxylation of a mixture of saccharose, propylene glycol
and water;
2. 35.0 parts of a polyether polyol having an OH number of 550, and was
prepared by the propoxylation of trimethylol propane;
3. 19.0 parts of a polyether polyol having an OH number of 435, and was
prepared by the propoxylation of a mixture of phthalic acid, sorbitol and
diethylene glycol;
4. 10.0 parts of tris (13-chloroisopropyl)phosphate flame retardant,
5. 0.7 parts of water as a co-foaming agent; and
6. 1.3 parts of a polyether polyol-modified polysiloxane foam stabilizer.
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The polyol formulations A and B were reacted in known manner, in accordance
with the formulations in Tables 1 and 2, to obtain rigid polyurethane foam
m ~tP.ri ~
The following isocyanates were used in the production of rigid polyurethane foam5 materials:
Isocyanate A: commercially available as Desmodurg) VP PU 1584 from Bayer AG (a modified Isocyanate based on Polymeric MDI with a NCO-
content of approx. 28.3%)
Isocyanate B: commercially available as Desmodur~) VP PU 1194 from Bayer AG
(a Polymeric MDI with a NCO-content of approx. 30.5%)
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Table 1: Rigid PUR foam materials cnnt~inin~ powdered fillers other than
PUR powder:
Comparison
Example Number 1 2
Formulation A 100
Formulation B - 100
Dibutyl tin dilauratel) - 0.012
Desmorapid~ PVl) - 0.25
Dimetlhjyl cyclohexyl
1 0 amine 1.3
Solkane S 141b,
Messrs. Solvay 22 23
Isocyanate A: - 122
Isocyanate B 175
1 5 Melamine2) (particle
size 0.04 mm) 5
Exolit 4223) (particle
size 0.024 mm) - 5
Gross density (kg/m3) 32.9 33.7
Vibration test,
600 rotations (Loss
of weight (%)) 11.8 10.7
heeated (gC) g 162 126
1) Catalyst
2) Melamine (grade 003, commercially available from DSM-Chemicals)
3) Exolit~ 422, (ammonium polyphosphate, commercially available from
Messrs. Hoechst)
Table 2: PUR rigid foam powder cont~ining PUR hard foam w
Comp. Examples according to the invention Comp. Examples according to the ~
invenhon c
Example number 3 4 5 6 7 8 9 10 11 u~
Formulation A 100 100 100 100 100 - -
Formulation B - - - - - 100 100 100 100
Dibutyl tin dilaurate - - - - - 0.012 0.012 0.012 0.012
Desmorapid ~) PV - - - - - 0.25 0.25 0.25 0.25
o Dimethyl cyclohexylamine 1.3 1.3 1.3 1.3 1.3
Solkane S 141B, Messrs 22 22 22 22 22 23 23 23 23
Solvay
Isocyanate A - - - - - 122 122 122 122
Isocyanate B 175 175 175 175 175
Pl~R Powder in foarn (wt%) - 3 5 10 5* - 3 3 5
Particle size (mm) - 0.5 0.5 0.5 0.5 0 5 1.6 0.5
* Inc. paper
:~,
Table 2: (Cont.) w
Comp. Examples according to the invention Comp. Examples according to the ~'
invention c
Example number 3 4 5 6 7 8 9 10 11
Gross density (kg/m3) 31.1 31.0 32.0 32.5 31.3 31.9 32.1 31.6 31.5
Vibrationtest, 600 rotations 6.7 6.1 5.6 6.1 6.4 4.8 5.5 4.3 4.9
(%)
Bending strength when 186 175 188 191 194 132 141 135 140
heated C
Shear strength (MPa) 0.15 0.16 0.17 0.17 0.17 1.18 0.18 0.16 0.17
Tensile strength (MPa) 0.26 -.34 0.33 0.32 0.32 0.41 0.41 0.41 0.43
Proportion of closed cells >91 >91 >92 >91 >92 92 96 95 94
(%)
o
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Following properties were identified from following methods: -
Table 1
Gross density DIN 53420
Vibration Test ASTM C-421
Bending strength DIN 53424
when heated
Table 2
Gross density DIN 53420
Vibration Test ASTM C-421
Bending strength DIN 53424
when heated
Shear strength DIN 53427
Tensile strength DIN 53430
Proportion of closed cells ISO 4590
15 Although the invention has been described in detail in the foregoing for the
purpose of illustration, it is to be understood that such detail is solely for that
purpose and that variations can be made therein by those skilled in the art without
departing from the spirit and scope of the invention except as it may be limited by
the claims.
